In the rich text editor:
@RoyalReality
In a comment:
[RoyalReality](https://chowlings.com/user/RoyalReality)
For Names and Avatars:
In the rich text editor:
%RoyalReality
In a comment:
[![RoyalReality's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/RoyalReality) [RoyalReality](https://chowlings.com/user/RoyalReality)